Approved Pipe Material for Pier/Dock Standpipe?

6/6/2023

Has anyone designed a dry manual standpipe for a pier or dock standpipe system in the past?

My question is in regards to materials used for the pipe.

With the tides rising and falling my client is struggling to find an approved material that will allow for enough flexibility.

I walked an adjacent marina to our project and it looked like they used 4" heavy-duty rubber tubing to run out the standpipe lines and transitioned to steel only for the vertical 2 1/2" up to the hose valves on the dock.

Any information to point us in the right direction would be helpful. Thanks in advance.

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11 Comments

David Kendrick

6/6/2023 08:12:20 am

Metraflex

https://www.metrafire.com/products-category/flexible-connector/

SCHULMAN

6/6/2023 08:19:20 am

NFPA 14: 4.2.6 says you can use any pipe as long as it is installed within the limits of its listing and per the manufacturer's instructions. So if it meets the pressure requirements and is installed correctly and passes tests you should be good. The rubber tubing sounds like a good idea for the use. Talk to your AHJ / Fire Marshall ... Best of luck

Dan Wilder

6/6/2023 08:25:19 am

While I have not designed one, what I've seen in the past:

Use of HDPE piping beneath with taps of stainless or galvanized (assuming, they were heavily painted) for the individual hose valves.

Straight carbon/stainless steel (again, heavily painted) and metraflex seismic assemblies.

Some older installations had what looked like a rubber bellows type assembly (likely not a fire protection listed assembly but just a solution implemented).

Something like a FlexHead Flexible Pipe, Metraflex FireStraight or even a "U" or "V" loop assembly come to mind as acceptable options for the movement.

Pete H

6/6/2023 08:53:37 am

Seeing the metraflex mentions here, I'll just mention that Reliable just dropped their equivalent "Rascoloop"

Joe F

6/6/2023 10:00:05 am

We have designed and installed a few in the past. We typically used SCH-80 PVC, and installed the piping between the dock joist below the deck boards to protect from physical damage, and sun damage over time.
Our transition to the gangway or ramp we used a heavy black hose found here:
https://www.continental-industry.com/en/solutions/fluid-handling/industrial-hoses/chemical-transfer-petroleum-hoses/products/petroleum-transfer-suction-discharge/plicord-super-black-flexwing.
Our manufacture would add Grooved Ends on the hose for connection to the dock piping. The hose valves were piped with Galvanized Sch-40, and connected to the supply pipe with Slip x Thread adapters.
Another major problem is the hangers or supports. Most are steel and will rust away quickly. We had better luck with Stainless Steel Banning Straps.

I would suggest looking into the HDPE as mentioned above. We did not have the tools required to join the large HDPE pipe and fitting.

Pete D.

6/6/2023 10:33:59 am

I would analyze the buoyant force acting on the pipe. I like the idea of using metraflex, but those are expensive.

Look at the highest volume of submerged pipe x the density of sea water, minus the pipe weight. You are looking at even load distribution along the path of the pipe, which should not create any deflection at the joints, unless part of the run is angled up or down and partially submerged.

I'd think you could resist the buoyant force using surge clips with your hanger rings or alternately using 138R split rings.

I would also consider the corrosion resistance of the material selected. You might consider cathodic protection for this.

Ryan Hinson

6/6/2023 12:30:53 pm

Be careful about use of HDPE (or any plastic pipe) in aboveground installation for FP as it is not listed for such use. Nor is any plastic listed in NFPA 14 (2016) Table 4.2.1 or for above ground installation per NFPA 24.

Since this pipe is normally-empty, there is no heat-sink to temper/delay pipe expansion due to ambient temperature changes.

Also, changes in ambient temperatures will result in expansion/contraction of the HDPE and proper support of such piping in accordance with mfgrs'/HDPE industry direction to allow expansion/contraction without creating trapped pockets is paramount. What are the conditions when it is installed versus the full ambient temperature range? How will it be completely drained? How will this piping be protected from direct sunlight? The surface temperature of HDPE piping in direct sun may be 50°F higher than the ambient temperature condition and the resulting effective pressure rating of of the piping is heavily dependent upon the maximum localized temperature to which the pipe may be exposed.

Without significant- and expensive plastic pipe protection considerations...and AHJ approval, I would recommend against using plastics in this scenario.

Metallic components with appropriate corrosion-reducing/mitigation measures would be the route I'd go...keeping in mind the galvanic corrosion potential recommended limit is 0.15 V in this harsh environment wherever dissimilar metals interact.

Colin Lusher

6/6/2023 01:13:21 pm

I've designed these for fixed piers in Hawaii, and we've used all stainless steel pipe and fittings. I'm not sure about the flexibility issue with your moving dock, but we used a metraflex at the point of connection from the pier to the land.

Scott Chambers/Champion fire design

6/9/2023 10:12:12 pm

I have run a few horizontal standpipes above and below a pier. Above we used galvanized and stainless steel with grooved ends. Below the pier was a bit more challenging both for corrosion resistance and durability from rising waters and the waves constantly crashing against it. Cement lined ductile iron pipe with flanged ends was found to be most durable. Of course securing it to the pier also plays a huge role in its longevity. They now make quite a bit of plastic and epoxy coated hanging materials which wouldn't be a bad idea to use. Good luck.

Shane Gilbertson

6/12/2023 12:49:37 pm

Following for ideas.
Here in Florida every beach jurisdiction requires something different, but nothing lasts long. of course cost is always an issue so stainless steel gets thrown out first. We do provide the Tar solution at all connections with Galv SCH40 pipe & fittings. HDPE and SCH80 PVC does not fair well with the Florida sun so I try give an option to wrap the pipe, at an extra cost of course. One main issue is if the dock can provide stability and durability of hanging ductile iron pipe while waves are bashing everything. I like the idea of using FlexHead or Metraflex, but also expensive.

Patrick Drumm

11/24/2023 03:10:18 pm

Although I meant to do this months ago, thank you to all you contributed to this discussion. It was very helpful in helping us come to a solution regarding materials on this project.

Approved Pipe Material for Pier/Dock Standpipe?

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